In fact, Ji Yansong did not know about the Sect Master's appearance through Bai Zhou.
When Bai Zhou found Jian Ai, he specially reminded him that the time was not ripe yet. She did not want to disturb others' lives, so Bai Zhou had always kept Jian Ai's news as the Sect Master a secret.
However, nothing in this world could escape Ji Yansong's divination. He had long calculated Jian Ai's appearance through said divination.
When Old Master Ji's fate reached its end, Ji Yansong had divined in advance and extended Old Master Ji's life at the last moment by sacrificing his lifeline.
Although he later learned through Bai Zhou that the Sect Master was a little girl, Ji Yansong could not hide his surprise now that he had seen it with his own eyes.
Other than Jian Ai's age, there was also the forbidden power of the ancient sect that her body had inherited—the power of blood!
